If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. Checkbox not checked

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).






SCHEDULE 13D




Comment for Type of Reporting Person:
All shares are held of record by Polaris V (as defined in Item 2(a) of the Original Schedule 13D (as defined below)). PVMC V (as defined in Item 2(a) of the Original Schedule 13D) is the general partner of Polaris V and may be deemed to have shared voting, investment and dispositive power with respect to these securities. The PVMC V Managing Members (as defined in Item 2(c) of the Original Schedule 13D) are the managing members of PVMC V and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by Polaris V. The percentage in Row 13 is based on 233,122,834 shares of Common Stock (as defined in Item 1 of the Original Schedule 13D) outstanding as of October 30, 2025, as set forth in the Issuer's quarterly report on Form 10-Q for the quarter ended September 30, 2025, filed with the United States Securities and Exchange Commission (the "Commission") on November 6, 2025 (the Form 10-Q).


SCHEDULE 13D




Comment for Type of Reporting Person:
All shares are held of record by Polaris EF V (as defined in Item 2(a) of the Original Schedule 13D). PVMC V is the general partner of Polaris EF V and may be deemed to have shared voting, investment and dispositive power with respect to these securities. The PVMC V Managing Members are the managing members of PVMC V and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by Polaris EF V. The percentage in Row 13 is based on 233,122,834 shares of Common Stock outstanding as of October 30, 2025, as set forth in the Form 10-Q.


SCHEDULE 13D




Comment for Type of Reporting Person:
All shares are held of record by Polaris FF V (as defined in Item 2(a) of the Original Schedule 13D). PVMC V is the general partner of Polaris FF V and may be deemed to have shared voting, investment and dispositive power with respect to these securities. The PVMC V Managing Members are the managing members of PVMC V and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by Polaris FF V. The percentage in Row 13 is based on 233,122,834 shares of Common Stock outstanding as of October 30, 2025, as set forth in the Form 10-Q.


SCHEDULE 13D




Comment for Type of Reporting Person:
All shares are held of record by Polaris SFF V (as defined in Item 2(a) of the Original Schedule 13D). PVMC V is the general partner of Polaris SFF V and may be deemed to have shared voting, investment and dispositive power with respect to these securities. The PVMC V Managing Members are the managing members of PVMC V and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by Polaris SFF V. The percentage in Row 13 is based on 233,122,834 shares of Common Stock outstanding as of October 30, 2025, as set forth in the Form 10-Q.


SCHEDULE 13D




Comment for Type of Reporting Person:
Consists of (i) 3,120,194 shares held of record by Polaris V, (ii) 60,814 shares held of record by Polaris EF V, (iii) 21,374 shares held of record by Polaris FF V and (iv) 31,198 shares held of record by Polaris SFF V. PVMC V is the general partner of each of Polaris V, Polaris EF V, Polaris FF V and Polaris SFF V and may be deemed to have shared voting, investment and dispositive power with respect to these securities. The PVMC V Managing Members are the managing members of PVMC V and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by each of Polaris V, Polaris EF V, Polaris FF V and Polaris SFF V. The percentage in Row 13 is based on 233,122,834 shares of Common Stock outstanding as of October 30, 2025, as set forth in the Form 10-Q.


SCHEDULE 13D




Comment for Type of Reporting Person:
All shares are held of record by Polaris IX (as defined in Item 2(a) of the Original Schedule 13D). PPGP IX (as defined in Item 2(a) of the Original Schedule 13D) is the general partner of Polaris IX and may be deemed to have shared voting, investment and dispositive power with respect to these securities. Terrance McGuire, an interest holder in PPGP IX and a member of the Issuer's Board (as defined in the Original Schedule 13D), and the PPGP IX Managing Members (as defined in Item 2(c) of the Original Schedule 13D) are the managing members of PPGP IX and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by Polaris IX. The percentage in Row 13 is based on 233,122,834 shares of Common Stock outstanding as of October 30, 2025, as set forth in the Form 10-Q.


SCHEDULE 13D




Comment for Type of Reporting Person:
All shares are held of record by Polaris IX. PPGP IX is the general partner of Polaris IX and may be deemed to have shared voting, investment and dispositive power with respect to these securities. Terrance McGuire, an interest holder in PPGP IX and a member of the Issuer's Board, and the PPGP IX Managing Members are the managing members of PPGP IX and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by Polaris IX. The percentage in Row 13 is based on 233,122,834 shares of Common Stock outstanding as of October 30, 2025, as set forth in the Form 10-Q.


SCHEDULE 13D




Comment for Type of Reporting Person:
All shares are held of record by Polaris HCT (as defined in Item 2(a) of the Original Schedule 13D). PHCT GP (as defined in Item 2(a) of the Original Schedule 13D) is the general partner of Polaris HCT and may be deemed to have shared voting, investment and dispositive power with respect to these securities. Terrance McGuire, an interest holder in PHCT GP and a member of the Issuer's Board, and the PHCT GP Managing Members (as defined in Item 2(c) of the Original Schedule 13D) are the managing members of PHCT GP and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by Polaris HCT. The percentage in Row 13 is based on 233,122,834 shares of Common Stock outstanding as of October 30, 2025, as set forth in the Form 10-Q.


SCHEDULE 13D




Comment for Type of Reporting Person:
All shares are held of record by Polaris HCT. PHCT GP is the general partner of Polaris HCT and may be deemed to have shared voting, investment and dispositive power with respect to these securities. Terrance McGuire, an interest holder in PHCT GP and a member of the Issuer's Board, and the PHCT GP Managing Members are the managing members of PHCT GP and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by Polaris HCT. The percentage in Row 13 is based on 233,122,834 shares of Common Stock outstanding as of October 30, 2025, as set forth in the Form 10-Q.


SCHEDULE 13D




Comment for Type of Reporting Person:
The shares reported in Rows 7 and 9 consist of 210,593 shares subject to stock options granted to Terrance McGuire in his capacity as a director of the Issuer that are exercisable as of the date of filing this Amendment No. 5 (as defined below) or within 60 days thereafter. The shares reported in Rows 8 and 10 consist of (i) 3,120,194 shares held of record by Polaris V, (ii) 60,814 shares held of record by Polaris EF V, (iii) 21,374 shares held of record by Polaris FF V, (iv) 31,198 shares held of record by Polaris SFF V, (v) 3,066,757 shares held of record by Polaris IX and (vi) 497,660 shares held of record by Polaris HCT. PVMC V is the general partner of each of Polaris V, Polaris EF V, Polaris FF V and Polaris SFF V and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by each of Polaris V, Polaris EF V, Polaris FF V and Polaris SFF V. The PVMC V Managing Members are the managing members of PVMC V and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by each of Polaris V, Polaris EF V, Polaris FF V and Polaris SFF V. PPGP IX is the general partner of Polaris IX and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by Polaris IX. Terrance McGuire, an interest holder in PPGP IX and a member of the Issuer's Board, and the PPGP IX Managing Members are the managing members of PPGP IX and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by Polaris IX. PHCT GP is the general partner of Polaris HCT and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by Polaris HCT. Terrance McGuire, an interest holder in PHCT GP and a member of the Issuer's Board, and the PHCT GP Managing Members are the managing members of PHCT GP and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by Polaris HCT. The percentage in Row 13 is based on 233,122,834 shares of Common Stock outstanding as of October 30, 2025, as set forth in the Form 10-Q, plus 210,593 shares subject to stock options held by Terrance McGuire and that are exercisable as of the date of the filing of this Statement or within 60 days thereafter.


SCHEDULE 13D




Comment for Type of Reporting Person:
Consists of (i) 3,120,194 shares held of record by Polaris V, (ii) 60,814 shares held of record by Polaris EF V, (iii) 21,374 shares held of record by Polaris FF V, and (iv) 31,198 shares held of record by Polaris SFF V. PVMC V is the general partner of each of Polaris V, Polaris EF V, Polaris FF V and Polaris SFF V and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by each of Polaris V, Polaris EF V, Polaris FF V and Polaris SFF V. The PVMC V Managing Members are the managing members of PVMC V and may be deemed to have shared voting, investment and dispositive power with respect to the securities held by each of Polaris V, Polaris EF V, Polaris FF V and Polaris SFF V. The percentage in Row 13 is based on 233,122,834 shares of Common Stock outstanding as of October 30, 2025, as set forth in the Form 10-Q.


SCHEDULE 13D


 
Polaris Venture Partners V, L.P.
 
Signature:/s/ Lauren Crockett*
Name/Title:Lauren Crockett/Authorized Signatory of Polaris Venture Management Co. V, L.L.C., the General Partner of Polaris Venture Partners V, L.P.
Date:11/07/2025
 
Polaris Venture Partners Entrepreneurs' Fund V, L.P.
 
Signature:/s/ Lauren Crockett*
Name/Title:Lauren Crockett/Authorized Signatory of Polaris Venture Management Co. V, L.L.C., the GP of Polaris Venture Partners Entrepreneurs' Fund V, L.P.
Date:11/07/2025
 
Polaris Venture Partners Founders' Fund V, L.P.
 
Signature:/s/ Lauren Crockett*
Name/Title:Lauren Crockett/Authorized Signatory of Polaris Venture Management Co. V, L.L.C., the GP of Polaris Venture Partners Founders' Fund V, L.P.
Date:11/07/2025
 
Polaris Venture Partners Special Founders' Fund V, L.P.
 
Signature:/s/ Lauren Crockett*
Name/Title:Lauren Crockett/Authorized Signatory of Polaris Venture Management Co. V, L.L.C., the GP of Polaris Venture Partners Special Founders' Fund V, L.P.
Date:11/07/2025
 
Polaris Venture Management Co. V, L.L.C.
 
Signature:/s/ Lauren Crockett*
Name/Title:Lauren Crockett/Authorized Signatory
Date:11/07/2025
 
Polaris Partners IX, L.P.
 
Signature:/s/ Lauren Crockett
Name/Title:Lauren Crockett/General Counsel of Polaris Partners GP IX, L.L.C., the General Partner of Polaris Partners IX, L.P.
Date:11/07/2025
 
Polaris Partners GP IX, L.L.C.
 
Signature:/s/ Lauren Crockett
Name/Title:Lauren Crockett/General Counsel
Date:11/07/2025
 
Polaris Healthcare Technology Opportunities Fund, L.P.
 
Signature:/s/ Lauren Crockett
Name/Title:Lauren Crockett/GC of Polaris Healthcare Technology Opportunities Fund GP, L.L.C., the GP of Polaris Healthcare Technology Opportunities Fund, L.P.
Date:11/07/2025
 
Polaris Healthcare Technology Opportunities Fund GP, L.L.C.
 
Signature:/s/ Lauren Crockett
Name/Title:Lauren Crockett/General Counsel
Date:11/07/2025
 
Terrance McGuire
 
Signature:/s/ Lauren Crockett*
Name/Title:Lauren Crockett/Attorney-in-Fact
Date:11/07/2025
 
Jonathan Flint
 
Signature:/s/ Lauren Crockett*
Name/Title:Lauren Crockett/Attorney-in-Fact
Date:11/07/2025
Comments accompanying signature:
[*This Amendment No. 5 was executed pursuant to a Power of Attorney. Note that copies of all applicable Powers of Attorney are already on file with the appropriate agencies.]